[dm-devel] xfs_btree_cur leak with 3.5-rc4

[Mike Snitzer]

I get kmemleak reports against XFS when I run the thinp-test-suite
against 3.5-rc4.  I didn't see any XFS leaks with 3.4.

kmemleak reports:

unreferenced object 0xffff8802767798a0 (size 208):
  comm "kworker/4:1", pid 25239, jiffies 4799921469 (age 5830.005s)
  hex dump (first 32 bytes):
    70 5c 6b ab 02 88 ff ff 00 58 0d 2c 03 88 ff ff  p\k......X.,....
    c0 8e 7d a0 ff ff ff ff 04 00 00 00 00 00 00 00  ..}.............
  backtrace:
    [<ffffffff814b6e3e>] kmemleak_alloc+0x5e/0xc0
    [<ffffffff8114c4b3>] kmem_cache_alloc+0x103/0x1d0
    [<ffffffffa078d987>] kmem_zone_alloc+0x77/0xf0 [xfs]
    [<ffffffffa078da1e>] kmem_zone_zalloc+0x1e/0x50 [xfs]
    [<ffffffffa0791c4c>] xfs_allocbt_init_cursor+0x4c/0xd0 [xfs]
    [<ffffffffa07902a8>] xfs_alloc_ag_vextent_near+0x68/0xb70 [xfs]
    [<ffffffffa0790e85>] xfs_alloc_ag_vextent+0xd5/0x100 [xfs]
    [<ffffffffa0791744>] __xfs_alloc_vextent+0x2a4/0x5f0 [xfs]
    [<ffffffffa0791ada>] xfs_alloc_vextent_worker+0x4a/0x80 [xfs]
    [<ffffffff8105a3f2>] process_one_work+0x132/0x450
    [<ffffffff8105c1fb>] worker_thread+0x17b/0x3c0
    [<ffffffff8106137e>] kthread+0x9e/0xb0
    [<ffffffff814d7ca4>] kernel_thread_helper+0x4/0x10
    [<ffffffffffffffff>] 0xffffffffffffffff

unloading the xfs module reports:

slab error in kmem_cache_destroy(): cache `xfs_btree_cur': Can't free all objects
Pid: 26305, comm: modprobe Tainted: G        W  O 3.5.0-rc4.cache+ #2
Call Trace:
 [<ffffffff8114ca3f>] kmem_cache_destroy+0xaf/0xe0
 [<ffffffffa0788074>] xfs_destroy_zones+0xc4/0x110 [xfs]
 [<ffffffffa07d32b3>] exit_xfs_fs+0x33/0x35 [xfs]
 [<ffffffff8109f82f>] sys_delete_module+0x1cf/0x2c0
 [<ffffffff810bb39c>] ? __audit_syscall_entry+0xcc/0x210
 [<ffffffff814d69a9>] system_call_fastpath+0x16/0x1b